1. Field of the Invention
The present invention relates to a robot control system for simultaneously controlling a plurality of robots and a robot equipment having the same.
2. Description of the Related Art
FIG. 24 is a block diagram showing a robot equipment 1 of the first conventional art. The robot equipment 1 of the first conventional art is composed of a plurality of industrial robots 2 to 4 and a plurality of robot controllers 5 to 7 installed respectively in the robots 2 to 4 for individually controlling the robots 2 to 4. The respective robot controllers 5 to 7 are connected to each other via a communication cable 8 (for example, refer to Japanese Patent Laid-Open Publication No. 2001-150372).
In the robot equipment 1 of the first conventional art, when performing a cooperative operation by the robots 2 to 4, the robot 2 among the robots acts as a master robot and the robots 3 and 4 other than the master robot act as a slave robot. The master side robot controller 5 for the master robot transmits data relating to the movement position of the master robot 2 to the slave side robot controllers 6 and 7 for the slave robots. The slave side robot controllers 6 and 7, on the basis of the data given from the master side robot controller 5, respectively control the slave robots 3 and 4 so that the slave robots 3 and 4 perform the cooperative operation with the master robot 2.
FIG. 25 is a block diagram showing robot equipment 10 of the second conventional art. The robot equipment 10 of the second conventional art is composed of a plurality of industrial robots 2 to 4, one main controller 11, and sub-controllers 12 to 14 installed respectively in the robots 2 to 4. The sub-controllers 12 to 14 have a servo amplifier for each of a plurality of actuators installed in each robot. The sub-controllers 12 to 14 are respectively connected to the main controller 11 via a communication cable 15 (for example, refer to Japanese Patent Laid-Open Publication No. 2001-100805).
In the robot equipment 10 of the second conventional art, the main controller 11 calculates the operation amount of each actuator installed in the robots 2 to 4 and transmits the calculation results respectively to the sub-controllers 12 to 14. The sub-controllers 12 to 14, on the basis of the position control data given from the main controller 11, give predetermined power to each actuator from each servo amplifier. By doing this, the motor connected to each servo amplifier is operated, thus each robot performs a desired movement operation thereof.
In the robot equipment 1 of the first conventional art, a teach pendant is provided in each of the robot controllers 5 to 7. Therefore, it is necessary for an operator to input individually a robot control program according to the operation procedure of the corresponding robots 2 to 4 to each teach pendant. Therefore, the program input operation by the operator becomes complicated. Further, the robot control program is individually inputted to the robot controllers 5 to 7, so that when performing the cooperative operation, to calculate the movement position of each slave robot, it is necessary to obtain the movement position of the master robot. Therefore, it is necessary to form the robot controllers 5 to 7 so as to communicate each other and the constitution of the robot equipment 1 is complicated.
Further, when performing the cooperative operation by the master robot 2 and the slave robots 3 and 4, it is necessary to synchronize the robot controllers 5 to 7 with each other. In this case, the variation in the control period due accumulation of a minute difference in the operation period between the robot controllers 5 to 7 and a minute difference between the transmission period and the reception period cannot be cancelled, thus a problem arises that the robot controllers 5 to 7 cannot be kept in the synchronization state.
In the robot equipment 10 of the second conventional art, the main controller 11, on the basis of an operation plan inputted from the outside, obtains the movement position of each of the robots 2 to 4, obtains the operation amount of each servo motor corresponding to each movement position by reverse conversion, and gives it to the sub-controllers 12 to 14. The main controller 11 must perform such calculations according to the number of robots. Further, as the number of axes of each robot increases, the calculation load applied to the reverse conversion increases. Therefore, when the number of robots and the number of axes of each robot increase, the load applied to the calculation of the main controller 11 increases and when the main controller 11 is realized by using a processing circuit at a slow processing speed, the robots 2 to 4 cannot be operated smoothly.